The King County Green Building Initiative started in 2001, and was included in the King Code Code with the Green Building and Sustainable Development Ordinance in 2008. The ordinance requires that all county-owned facilities and financial capital projects be built to LEED Gold standards, including new construction, major renovations, and projects using alternative funding. Major renovations are defined in the statutes as work that affects more than twenty-five percent of a building's square footage when the affected space is 5000 square feet or more. Projects must achieve Gold certification if the certification can be achieved with "no incremental cost impact to the current expense fund over the life of the asset and an incremental cost impact of no more than two percent to other funds over the life of the asset, as compared to a project that is not seeking a LEED rating." Any projects that are not able to meet the Gold standard for financial or technical reasons must incorporate methods from the Sustainable Infrastructure Scorecard.

In 2010, Ordinance 16769 also added efficient lighting requirements to the Green Building and Sustainable Development section of the code.